Cheapest/Fastest way to get 12 CR?

[LuckyLion44]

For me the cheapest way to get 12 hours was, in a past life, to be a tenured (non-"Other Personnel Services") employee of the State of Florida's government.
This allows you to take 6 credit hours a semester with a tuition waiver from the nearest university. Two semesters and there you have it!

The downside was that your co-workers will mostly be people from Florida.

I concur -- being a staff member for the university (or even for the state/county/city/fed is a good way to go). Alternatively, the graduate assistantship option with full tuition remission + stipend. Lastly, become a hall director for residential life to pay down loans fast.